Despite of the fact that Microsoft’s next-generation graphics application programming interface (API) will be able to take advantage of unified shader processors, at least Nvidia Corp.’s first DirectX 10-capable chip will utilize more traditional dedicated pixel and vertex processors, according to some rumours.

Nvidia’s code-named G80 graphics processing unit (GPU) will incorporate 48 pixel shader processors and an unknown number of vertex shader processors, some unofficial sources said. The chip is still expected to support feature-set of DirectX 10 along with Shader Model 4.0, even though it will not take advantage of the unified shader processors that can compute both pixel and vertex shaders.

Microsoft Corp. pushes unified shader language for pixel and vertex shaders in its Xbox 360 game console ad well as graphics API of Windows Longhorn – Windows Graphics Foundation 2.0, which is sometimes referred as the DirectX 10. As a result of that, graphics hardware designers should deliver their chips with unified shader engines at some point in future in order to more efficiently support the new API. However, previously Nvidia Corp. expressed opinion that it would be necessary to release an architecture with unified shader processors “when it makes sense”.

“We will do a unified architecture in hardware when it makes sense. When it’s possible to make the hardware work faster unified, then of course we will. It will be easier to build in the future, but for the meantime, there’s plenty of mileage left in this architecture,” David Kirk, who is Nvidia’s chief architect, said in an interview with Bit-tech.net web-site.

ATI Technologies has already developed a unified shader architecture used in the Xenos graphics processor of the Xbox 360 game console. Nvidia believes that it is much harder to design a processor with unified pixel and vertex shader processors, as it is not a trivial task to create appropriate load balancing logic that would arbiter the unified arithmetic logic units.

The new DirectX 10 API is expected to be released later this year along with Microsoft Windows Vista operating system.

Nvidia did not respond to enquiry seeking for comment. Typically, the company does not comment on unreleased products.